Ultrasonic cleaning machine is a common cleaning equipment that uses the high-frequency vibration of ultrasound to clean the surface and interior of objects. If the cleaning machine is working but there is no ultrasonic sound, it may be due to the following reasons:

1. Insufficient ultrasonic output: The ultrasonic cleaning machine needs to generate high-strength ultrasonic vibration to clean objects during operation, and these vibrations need to be transmitted through water or other media. If the output of ultrasound is insufficient, it may not be able to transmit to the medium or the surface of the object, resulting in a situation of no sound.

2. Ultrasonic sound is isolated: The high-frequency vibration of ultrasonic waves will be reflected, refracted, and scattered in the medium, and will be hindered in its transmission process. If the ultrasonic sound is isolated, such as due to the sound insulation cover of the cleaning machine or the good sealing of the sink, it may also lead to a situation of no sound.

3. Ultrasonic generator failure: The core component of the ultrasonic cleaning machine is the ultrasonic generator. If a failure occurs, it may result in no sound. For example, the generator may experience short circuits, open circuits, and other issues, resulting in the inability to generate ultrasonic vibration normally.